CLAS physics database search results Measurement E151M1569 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.55 222 -0.3813 0.8818 0.0377 0.55 234 -0.6063 0.5654 0.0472 0.65 138 1.4145 0.9502 0.0875 0.65 222 -1.8916 0.8937 0.1173 0.65 234 -0.4303 0.6555 0.0566 0.75 162 -2.2388 0.7507 0.1336 0.75 222 0.8579 1.2275 0.0582 0.75 234 1.6879 0.6472 0.1026 0.85 210 -0.12 1.0713 0.0308 0.85 222 -0.5907 0.9295 0.0456 0.85 234 0.9248 0.8762 0.0616 0.65 246 -1.3614 0.7459 0.0869 0.75 234 1.0022 0.7121 0.0671 0.75 246 -0.2963 0.9413 0.0349 0.85 234 0.2006 0.8445 0.0323